indahl



M. C. INDAHL.

DIFFERENTIAL MECHANISM. APPLICATIONl FILED JULY 24. 1917.

Patented Dec. 9,1919. 6 SHEETS-SHEET l C. INDAHL.

DIFFERENTIAL MECHANISM.

APPLICATION FILED IuLY 24. I9I1.

II III' f5 M. c. INDAHL. DIFFERENTIAL MECHANISM.

Patented Dee. 9, 1919.

l 6 SHEETS-SHEET 3.

Nl. C. INDAHL.

DIFFERENTIAL'MECHANISM.

APPLICATION FILED IULY 24. Isn.

I l l l l l W y "u u @vH/maw t Patented Dec.' 9, 1919.

M. CnINDAHL. DIFFERENUAL MECHANISM.

APPLICATION FILED JULY 24. |917.

Patented Dec. 9, 1919.

6 SHEETS-SHEET 5.

IVI. C. INDAHL. DIEFERENTIIILAMECHANISM, APPLICATION FIL ED JULY 24. |917.

Patntedeo.

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, sra'rns PATEN' iviaumrz c. INDAHL, or PHILADELPIA, PENNSYLVANIA.

. /mPPERENTIAL MECHANISM.

i Y Application filed July 24, 1917, Serial No. 182,516.

To-aZZ whom t may concern: Be it known that I, MAURrrz C. IiinAHL, a citizen of the United States, residing at Philadelphia, in the county of Philadel-v i y forming part of this specification.

The present invention relates to differential mechanism and has for its primary ob ject the provision of an improved'and eiiicieiit means for limiting the ratio of differentiation of a. differential gear to a predetermined maximum ratio.

In my co-pending application, filed March 8, 1916, Serial No. 82,929, I have disclosed and claimed broadly a positive operating means for limiting the ratio of diii'erentiation of a pair of'driven members,fconnected bya differential mechanism, to a predetermined maximum ratio; and in said cepending application I have vfully set forth the advantages of a mechanism of this character,

of which a brief statement will now be given.

The utility of mechanism of the generic ktype disclosed in both the former and the present application is especially great when the mechanism is employed in 'connection with differential gears for motor driven vehicles, such as automobiles, wherein the pur pose of the differential gear is to divide the power from the motor equally to the two driven members of a di-vided shaft, and in such manner that the relative speeds of the two driven 'members may be changed by outside conditions, ,without yeffecting the motor. As previously stated, differential gears embodying this principle give perfectly satisfactory results, in so far as they permit the wheels t0 run with perfect freedom at the speed determined by the size of the wheels so longv as'rthe resistance on each wheel is enough to consume one-half of the i driving power. When, however, the resists ance on one of the wheels, which, in ,the case of an automobile, is the traction of the wheel,

is less than one-half the driving power, or'

the power distributed to that wheel, the wheel begins to slip, and as the gearing is always equalizing the power between the two wheels or driven members, theresu'lt is that the other wheel whichinay have plenty yof resistance or' traction will receive only f Specification of Letters Patent.

Patented Dec. 9, i919.,

the same amount of power as consumed by 1the wheel that is slipping. The power which may be utilized being determined by the wheel having the least resistance or traction, a large amount of driving powei` will consequently be lost by the vehicle at a time when a maximum driving power is most essential.v This feature of disadvantage is undoubtedly one of the primary causes of the tendency of automobiles to skid on slippery roads, when turning, and even when the veliicle is ruiming straight ahead.A

-erning or controlling means is actuated to positively prevent any further difference in their relative speeds. For-example, if the wheel of one of the driven mciiibers starts to slip, the increase in speed will .be accompanied by a proportionate decrease in,l speed of the other driven member; As the-'speed of the slipping wheel increases, speed of the other wheel decreases proportionately, and, finally, when amaxinium di ,-ereiice in the relative speeds is reached, the diifereni tial. gear will be. positively prevented from permitting any further differentiation of the relative speeds. Consequently, the slipping wheel will not be able to acquire any further momentum; neither will the other wheel be retarded further. The result is that no further diferentiation being permitted, the two 'driven members or wheels will quickly regain their normal equalized speeds, and this without any great loss of power, because of the positive limitationv imposed upon the' slip of either of the two wheels. If the invention is utilized in an automobile, the predetermined maximum lratio of diiferentiation, beyond which no further differentiation can take place, will be calculated from the shortest turning radius of the vehicle, since it is absolutely necessary, in this application of the invention, that `differentiation be allowed up to the point of permitting the vehicle to make the shortest possible turn.

The above is descriptive of the broad principle' involved in the inventionpdisclosed by the present application. The difference between the present invention and that disclosed in -my said co-pending application lies in the mode of preventing diiferentiation of the driven members beyond a predetermined maximum ratio; in other Words, in the character of governing mechanism employed and in the way the controlling action or force is applied to the dierential.-

A full understanding of the invention will be attained from the ensuingl detailed de.

scription, when taken in connection with accompanying drawings, which illustrate a structural embodiment of the invention'in a preferred form. VThe `novel features of the invention will be particularly pointed out and specified in the claims at the end of the specification.

l In the drawings A Figure l is a horizontal sectional elevation of one well known type of balanced differential gearing provided withthe present improvements.

Fig. 2 isa vertical sectional elevation of the rotatable casing or gear carryingclage.

Fig. 3 is an end elevation of the same.

Fig. 4 is a transverse section taken in a plane indicatedv bythe line 4-4 ofv Fig. 1.

Fig.' 5 1s a transverse sectional elevation taken 1n a plane indicated by the line :5-5

of Fig. 1.

Fig. 6 is a section on the line 6*-6 of Fig. 5.

Fig. 7 isa side elevation of the outer casing viewed from the right of Fig'. 1.'

Fig. 8 is a detail planof the parts shown in Fig. 7.

Fig. 9 is a section on the line 9-9 of Fig. 3.

Fig. 10 is a sectional plan View of a differential gearing equippedsvith single re- Iversible clutches.

illustrated in the accompanying drawings,

may be -of the well known balanced type, such as is commonly employed in automobiles, wherein the power from the motor` is equally distributed tothe two driven members of a divided shaft, or wheel axle. In the *form shown, the differential gearing is of the 'bevel gear type adapted tobe mounted within the stationary outer casing or shell 1. 'Ihe latter is provided with suitable xtension's orsleeves 2, 3, centrally located in the respective right and left hand sides of the shell and in which elongated:

are rigidly7 mounted the right and left handv in ',Figs.

portion of the shellv or cage by ings.

hollow shafts 4, 5. lVitliin said fixed shafts 4, 5, are the right and left hand driven members 6, 7, of a divided wheel axle. In the present instance, it will be understood that each driven member 6, 7, supports and drives at its outer end a. wheel, the pair of wheels so supported and driven being usually the Rotatably rear wheels of an automobile. mounted within the outer case 1 is an inner shell -or cage consisting. of right and left hand members 8, 9, suitably bolted together y bolts 10, as illustrated more particularly 2, 3 and 9. The inner shell or cage is provided at its opposite sides with right and left hand sleeves 11, 12, which are respectively joined with the main body webs 13, see Figs. 2, and 3. These sleeves are supported at their outer extremities within suitable antifriction radial and thrust bearings 14, l5, within the outer' casing 1, as shown in Fig. 1. ,l

The inner shell or casing is provided with a large bevel gear 16 in mesh with a bevel pinion 17 carried by a shaft. 18, which enters the opening in the inner end of the vouter casin as shown in Fig. 1.v In the present em odiment of the invention, the shaft 18 is the Cardan or transmisison shaft of a motor driven vehicle,` and is adapted through the intermediary gearing above set forth to rotate the inner shell in the usual way. Fixed respectively rto the driven members 6, 7, are the usual right and left hand driven bevel gears 19, 20, both of which are in mesh with the usual compensating bevel` pinions 21. The compensatingv pinions- 21 are preferably four in number arranged at quadrature in the rotating shell and are` l respectively journaled on the radial pins a spider 23 located withinthe inner shell. The extremities of the radial pins 22 extendinto bearings 24 formed in the rotating shell and thereby hold the spider 23 in proper position. This construction is illustrated in`detail in Fig. 4 of the draw- The operation of diferentiabgearing of this type is well known in the art, it being sufficient to state that tthe several pinions 21,' serve to distribute the power from the large gear 16 equally to the driven gears 19, 20, and also permit one driven member to revolve with a grealte;l speed than the normal drive, aocompanied'b-y a proportional reduction in speed ofthe other driven member, and this, without in any way disturbing the Cardan or transmission, shaft 18.

'Ilhe present invention resides particularly in the novel governing means for defining the ratio of differentiation o`f the drivenV members 6, 7, orto be more explicit, by the present arrangement, when the vdifferential gearing is being operated to permit dierential movement and one driven member is rotating at an accelerated rate ofvspeed with a proportional diminished rate of speed in the other driven member, the speed of one driven member cannot be accelerated beyond a predetermined maximum limit and conversely the speed of the other driven niember cannot be further -dimin1shed, but the entire available power will be' utilized in the driving eort. The present improved mechanism for applying this principle 1n the operation of a differential gear will now be described. j

Referring particularly to Figs. 1 to 9, inclusive, the hubs 21a' oftwo of the com; pensating pinions 21, for example, the pair illustrated in F ig. 1, carry the controlling `or governing gears'25, 26, the hubs 25a, 26"l of the latter being respectively, keyed to lsaid pair ofhubs 21a. These gears 25, 26,

are-disposed diametrically with. respect to the driven members 6, 7, as viewed in Fig. 1

. and the toothed portions 25h, 26b of the gears are Iin mesh with teeth of gears 27, 28, journaled on the sleeves l1, 12. Each gear 27,28 has an extended hub 27a, 28a and keyed to these extended hubs are the inner ring members 29a, 80a of two pairs of clutches 29, 30. One pair of clutches 29 is intended'to lock the gears 27 28 against reverse rotation, but

' to permit forward rotation of the latter,

whereas the other pair of clutches 30 will lock said gears against forward rotation but permit reverse rotation of the gears. Each member of the pair of' clutches 29 consists (Fig. 5) of inner and outer rings 29a, 29",

the inner rings 29a having inclined roller recesses 29c within which are located rollers 29d.` The said roller recesses 29c are inclined toward the inner circumferential edge of the inner rings in the direction of forward rotation of said ring. A cage 29e is provided between the inner and the outer rings 29a, 29h, for the purpose of keeping the rollers in place in their respective recesses. The construction of the pair of clutches 30 is similar to the pair 29, each clutch 30 consisting of an inner ring 30*l and an outer ring 30b between which are rollers ()ci working in recesses 30C and retained in place by a cage 30e. In the pair of clutches 30, however, the recesses .30 are inclined in opposite direction to the recesses of the pair of clutches 29, whereby the clutches 30 will become effective on forward' rotation of the inner rings relatively to the outer rings,.in stead of on reverse rotation, as will hereinafter appear. i

The operation of the mechanism thus far described is as follows: Assuming that the members 6, 7, are being driven forwardly and that it is desired to connect the governing means for operation to prevent differentiation of the driven members beyond a maximum ratio, the outer rings-29b of the pair of clutches 29 will be locked lagainst rotation in either direction, preferably by ldriven member 6 is drive of the members 6, 7, since the rollers 29d will climb the inclines of the recesses 29n in the inner rings 29a, as soon as the latter, which are keyed to the gears27, 28, start to rotate in reverse direction. Thus, the rollers v 29d, after they climb out of their recesses, will engage the fixed or locked outer rings 29b and lock the inner rings 29a together with the gears 27 28, to the fixed outer rings. The more power that is lapplied tending to rotate lgears r27, 28, reversely, the tighter will become the engagement of the rollers with the fixed outer rings, and hence, the more effective the locking action of the clutches 29 with relation to the gears 27, 28. On forward rotation of gears 27 28, however, the rollers 29d remain in the lower portions of their respective recesses 29c and no resistance is offered to forward rotation of the inner rings 29a and said gears 27 28. When the clutches are set for operation in the manner above described, the outer rings 30b of the pair o f clutches 30 are disconnected from the -stationary outer casing and thus all the members of said clutches 30 will revolve freelywith the gears 27 28 without affecting rotary movement of the gears 27 28 in either direction.

Under normal conditions, l1'. c., when the driven members 6, 7 are rotating forwardly travel in unison, carrying around with them the compensating pinions 21 and the governing gears 25, 2G. As long as the resistance on said driven members 6, 7, remains substantially equal, the above stated conditions will prevail and no movement of thc pinions 2l and the governing gears 25, 2G on their individual axes will take` place. Gears 27, 28 will also rotate forwardly with the train of differential gears, without resistance, since the clutches 29 do not operate on forward rotation of the gears 27, 28, and the clutches 80 are'not set for operation on forward drive, as Vhereinbefore stated. lVhen one of the forwardly diiven members 6, 7 ,accelerates in speed relatively tol the rotating shell, the compensating pinions 2l are rotated on their individual axes, and the speed of the other driven member-is diminished relatively to the rotating shell. Assuming, for present purposes, that the speed of the left hand driven member 7 (as viewed inv Fig. 1) lis acceleratedand that concurrently the speed of the right hand driven member 6 is retarded. At this time, the resistance to forward drive of the right hand greater than the resistance on the left hand driven member 7,

which diminishes as the latter gains/speed. The compensatin pinions 21 are now rotating on their in ividual axes and will tend to drive the member 6 rearwardly although this tendency is resisted and met by the forward drive of the differential gearing,

through the large gear 16. The result isA thatthe compensating pinions 21 begin t0 describe a planetaryl movement around the gear 19 of the driven member 6 in the manner of pinions traveling aro-und a fixed rack. Theigreater the resistance to forward drive of the member 6 through its gear 1.9, the slower the speed of the latter, and, hence, the greater the loss of power, because of the said planetary movement of pinions 21. As ,h

a result, 1f the ratio of differentiation of the driven members 6, 7, were permitted to increase to an extreme point, the retarded member 6 would stop rotating altogether, i .iile all the power would be. consumed in rapidly spinning the other driven member 7, a very undesirable situation for a motor car in particular. But'the governing gears 25, 26 are also journaled on the axes of two of the, compensating pinions 21 and hence when the resistance to forward drive of the gear 19 of driven member 6 is great enough to overcome the forward drive of the gear 27 which is transmitted normally by the planetary movement of governing gears 25, 26, the rotation of the gears 25, 26 on their own axes will be appliedto rotate gear 27 reversely, whereupon the clutch 29 of the latter will become effective to lock gear 27 against reverse rotation and hence the speed of gears 25, 26 on their own axes cannot be further' increased. As the speed'of gears 25,

,26 on their individual axes cannot increase,

itfollows that the pinions 21 cannot be further acceleratedI on their individual axes, and hence no further differentiation in speed between the gears 19 and 20 of the driven members 6 and 7 can take place. Thus, when the clutch 29 on tlieright hand gear 27 locks ear 27 against reverse rotation, the locking positively prevents thev ratio of differentiation from. increasing, although the gears maycontinue to differentiate at the maximum ratio. Hence no undue stress orVl strain is transmitted to the gears, such for example, as'wouldf occur if all diEe'rential action were suddenly stopped. In automobile practice, it is of course desirable that 4differentiation* of the driven members 6, 7, be perinltted` to a sufficient ratio, whereby the vehicle may be turned on its shortest turning radius. ABeyond this, noA further differentiation in speed of 4the driven members is necessary, and the gearing, willbe' so proportioned. that the governing or limiting action of gears 25', 26 will commence, when the ratio of differentlation increases to an unnecessary amount.

' referate.

It will be understood by those skilled in the art that the gear ratio will determine the maximum ratio of differentiation, beyond which no further differentiation can take place. `By way of explanation, however, it may be stated that the determination of the governing action of the gears 25, 26 will largely depend upon their size relatively to the pinions 21 and the gears 19, 20, since the greater the size of the gears 25, 26, the more leverage which must be exerted by a retarded gear 19 or 20 through the pinions 21 vto rotate the gears 27 or 28 in reverse direction and cause the clutches 29 to lock said .gears 27, 28.

During the above described operation gear 28 on the left hand side ofthe compensating pinions 21 will be driven forwardly. When, however, driven gear 19 is accelerated in speed and driven gear 20 retarded, the compensating pinions 21 will be rotated on their individual axes and concurrently the governing gears 25, 26 in reverse direction to that previously set forth, z'. e., when driven gear 20 isl accelerated and driven gear 19Yretarded. Hence,

the force will be'.

exerted by the governing gears 25, 26 to drive the left liand gear 28 reversely instead of the right han'd gear 27. The clutch 29 on the left hand side will act at this time, and tlieright hand gear 27 will be driven forwardly.

A further advantage of the governing mechanism above described lies in the fact that reverse rotation of either ofthe driven members 6, 7, is absolutely prevented when the parts are set for operation, on forward drive.' If either driven member starts to rotate reversely, the reverse rotation of such l driven member will be communicated to the compensating pinions 21, causing the latter l to rotate on their individual axes, and also the .governing gears 25, 26, which will immediately try to rotate reversely a gear 27 or 28, depending upon which driven member slips backward. As .before explained, the clutches 29 become effective. immediately upon an gears 27 28, so that the gears will be positively locked against reverse .rotation of the driven members on forward drive. ThisI provides an effective check against backing down grade should the power fail.

Un-,reverse drive, the clutches 29 will be disconnected by freeing the outer rings 29b from the stationary casing and the clutches 30 connected by locking the outer rings 301 to the casing. The operation is just the same. as that heretofore explained, except that the direction of motion of all the gears is reversed. If a driven member starts yto slip and the other is retarded to the maximum ratio of differentiation in speed, the gears 25, 26 will try to rotate one. of the gears 27 28 forwardly, whereupon the corattempted reverse rotationi of the responding clutch will become Aeffective to prevent further differentiation of the driven members in reverse direction. Concurrently, thegears will lock when a driven member starts to rotate forwardly when the clutches 30 are set for operation on reverse rotation and the clutches 29 disconnected.

The mechanism for controlling the two pairs ofclutches illustrated i1' Figs. 1 to 9, inclusive, will now be described. As shown, the two outer rings 29b of pair 29, and similarly, the two outer rings 30hd of pair 30, are formed with toothed peripheries, adapted respectively to be engaged by the two pairs of locking pins 31 and 32. The locking pins 31 for the pair of rings29b are arranged at opposite ends of the differential, as are the locking pins 32 for the other pair of rings 30". Mounted in a suitable bearing 33 formed on the outer face of the stationary casing, is an operating shaft 34 having a pair of long tooth pinions or toothed sections 35, and the upper ends `of the locking` pins 31 and 32 are respectively formed with racks 36[ adapted to engage opposite sides of pinions on the operating shaft. Said locking pins .are slidably mounted in suitable bearings 37, 38, formed in the wall of the stationary casing. .Any suitable means may be provided for oscillating-.shaft 34, which movement is preferably controlled by afoot pedal (not shown), but of the usual type. Oscillation of shaft 34 inj one direction will force the pins 31 into engagement with the teeth lof rings 29h, by reason of the engagement of pinions and racks, thereby locking said rings 291 to. the outer casing. Simultaneously, the pins 32 will be retracted from engagement with rings 30. If the shaft 34 is oscillated in reverse direction, the pin's 31 will be retracted from engagement with rings 29b and simultaneously locking pins 32 will be forced into engagement with rings 30".

In-the embodiment of the invention illustrated in'Figs. 10 to 1'4, inclusive, a single reversible clutch is provided at each end of the differential gearing for the gears 27, 28, instead of the clutches 29,- 30, at each end, as hereinbefore described. A ring 39 surrounds the sleeve of each pinion 27, 28, and is provided with a plurality ofrecesses 39"l in its inner circumferential surface, as shown. These recesses are all inclined away in both directions from the bottoms of the recesses and are adapted to receive rollers- 40, which are held in place in their respective recesses by engagementwith the projecting members 41a' of a cage 41. Said pro.

ject from a ring 41 in lines parallel with the longitudinal axis of the ring. Projecting from the periphery of ring 4l is an ear 42, as shown more particularly in Fig. 12. These ears 42 are adapted to engage the ends of pluri-gers 43 slidably mounted in sockets in-the fixed casing. Springs 47 located in the sockets beneath the plungers 43 exert pressure in a direction to force the latter out of their sockets, and thus oscillatory movement of the ring41 and its connected cage in both directions is yieldingly resisted. J ointed to the outer ring 39 on opposite sides of its central longitudinal axis are the lower ends of .links 48, 49. The upper ends'of these links are in turn-jointed to the ends of bell crank'toggle arms 50, 51, journaled on thev rock shaft 52. Said shaft 52 is itself journaled in bearings 53, 54, in the fixed outer casing or lgear box, as shown in Fig. 10, and has yoke-like arms 55 fixed thereon in position to embrace the bell crank toggle arms 50, 51. The intermediate part 55a `(dotted lines Fig.,11) plays between the toggle arms 50, 51 and is adapted when the shaft is rocked to swing the toggle arms in one direction or the' other and to thereby rturn the ring 39 in one direction or the other. Secured to the rock shaft 52l is an arm 56 whichis adapted to have a suitable manual or pedal connection for operating the shaft, said connection not beingv illustrated herein, but of any construction preferred by those skilled in the art.

AThe operation ofthe above set forth re- Jversible clutch is as follows: When it is desired to set the clutch for operation to prevent reverse rotation of the pinion 27, i. e., "when the driven members, 6, 7, are operating' on forward drive, yas heretofore explained, the rock shaft 52 is given a clockwise turn, until 'the parts assume the position shown in Fig. 11. VThis will shift the outer ring 39V so that Vthe rollers 40 are locatedl on vthe left-hand side of the transverse central axial lines of therecesses 39a in said outer ring. Consequently, when pressure is exerted by the governing gears 25, 26,- attempting to rotate gear.27 reversely, the rollers'40 will ride up the inclines of the recesses 39a. and lock the'hub of gear 27 to the outer ring 39. On moving the shaft 52 so that the parts are shifted into position, the reverse of that. shown in Fig. 12, the ring v39. in turn is moved to position the centers of the vrecesses 39a on the left Lf the rollers so that the clutching action will become effective on forward rotation of gear 27 instead of on reverse rotation. A spring 508L is preferably bridged between the toggles and exerts its tension in a direction tending tohold the toggles in one or the other of their positions Aof adjustment, or in an intermediate position of adjustment, as the case maybe. The cage be certain and If the toggles l are left in an intermediate position then the clutch rollers will beheld 'opposite the deepest parts of the recesses and'no clutching action will take place in either direction, under which circumstances the positlve gear ratio between the driven members is out of action and .ordinary differentiatlon may y take place without limit.

It will be understood that a clutch similar to the one just described is also provided for the gear 28,'and that the clutch of gear 28 will vbe locked against reverse rotation concurrently with the clutch of gear 27er,

What is claimed is: 4

l. The combination with a pair of driven members,l and differential mechanism interposed between said members for permitting acceleration in speed of one of the driven members accompanied by a proportionate diminution in speed of the other driven member, said differential mechanism including the usual driven gears carried respectively by the driven members and the usual compensating pinions interposed between and in mesh with said driven gears, of a positive operating means acting through a compensating pinion for limiting the ratio of differentiation of said driven members to a predetermined maximum ratio.

2. The combination with a pair of driven members, and differential mechanism inter! posed between said members for permitting acceleration in speed of one of the driven members accompanied Iby a proportionate diminution in speed of the other driven member, said differential mechanismincluding the usual driven gears carried respec-` tively by the driven members and the usual compensating pinions interposed between and in mesh with said driven gears, of means responsive ,to a predetermined acceleration in speed of a compensatin pinion for limiting the ratio the driven members to a predetermined maximum ratio.

3. The combination with a pair 4of driven members, and differential mechanism interposed between said members for permitting acceleration in speed of one of the driven Imembers accompanied by a proportionate positive operating means acting through acompensating pinion for limiting the ratio position of the ring 39 so of differentiation of of differentiationl of said driven members toa predetermined maximum ratio and also for preventing reverse rotation of the driven.members.

4. The combination with a pair of driven members, and differential mechanism interposed between said members for permitting acceleration in speed of one of the driven members accompanied by a proportionate diminution in speed of the other driven member and differential mechanism including the usual driveny gears carried respectively by the driven members and the usual compensating pinions interposed between and in mesh` with said driven gears, means responsive to a predetermined acceleration in speed of a compensating pinion for limiting the ratio of differentiation of the driven 'members to a predetermined maximum ratio and also 'for preventing reverse rotation of the driven members.

5. The combination with a pair of driven members, and differential mechanism interposed between said membersfor permitting acceleration in speed of one'of the -driven members accompanied by a proportionate diminution in speed of the driven member, said differential mechanism including the usual driven gears carried respectively by the driven mem'bers and the usual compen- 'satingpinions interposed between and in ofl and in mesh with lsaid driven gears, governing mechanism. actuated-by a compensating pinion for limiting the ratio of differentiation `of'the driven members to a predetermined maximum ratio, and also for preventing reverse rotation' of the driven members.

7. The combination with a' pair of driven members and differential mechanism interposed between said members for permitting acceleration Iin speed of one of the driven' members accompanied by a proportionate diminution in speed of the other driven member, said differential mechanism including the usual driven gears carried respectively by the driven members and the usual compensating pinions interposed between and in mesh with said driven gears, of a governing member driven by a compensating pinion, and means for preventing acceleration of said governing member beyond a predetermined maximum rate of speed with ,relation to the speed of' the driven members.

8. The combination with a pair of driven members and differential mechanism interposed between said members for permitting acceleration in speed of one of the driven members accompanied by a proportionate diminution in speed of the other driven member, said diiierential mechanism including the usual driven gears carried respectively by the driven members and the usuall ing the usual driven gears carried respectively by the driven'members and the usual compensating pinions interposed between and in mesh with said driven gears, of a gear, another gear driven by a compensating pinion and exerting pressure in a direction to drive said first named gear revcrsely, and means for preventing reverse rotation of said first named gear. l

10. The combination with a pair of driven members and differential mechanism interposed between said members for permitting4 acceleration in speed of one of the driven members accompanied by /a proportionate diminution in speed of the other driven member, said differential mechanism including the usual driven gears carried respectively by the driven members and the usual compensating pinions interposed between and in mesh with said driven gears, of a gear, another gear driven by a compensating pinion and 4exerting pressure in a direction to drive said first named gear reversely, and

a clutch for preventing reverse rotation of said first named gear.

l1. The combination with a pair of driven members, and differential gearing interposed between said members for permitting acceleration in sp'eed of one of the driven members accompanied by a proportionate 'diminution in sipeed of the other driven memlber, said di erential gearing including the usual driven gears carried respectively by the driven members and the usual compensating pinions interposed between and in mesh with said driven gears, of means for positively limiting 'the acceleration in rota` tion on its'own axis which can be acquired by a compensating pinionduring diii'erentiation of the gearing without arresting or retarding diii'erentiation less than the permissible maximum.

l2. The combination with a pair of driven members, and differential gearing interposed between said members for permitting acceleration in speed of one of the driven members accompanied by a proportionate diminution in speed of the other driven member, said differential gearing including the usual driven gears carried respectively by the driven members and the usual compensating pinions interposed between'and in mesh with said driven gears, of a gear train connected with said differential gearing and operative to prevent differentiation in the relative speeds of the driven members beyond a predetermined maximum ratio of differentiation.

13. A motor vehicle drive gearing embodying the following instrumentalities, towit, a drive shaft, independent driven axles, a differential caring interposed between the drive sha-iiif and axles and having a compensating pinion through which the power is distributed to the axles and manul ally controlled gearing connected with said pinion for determining the rotation of the latter on its own axis at a desired speed, to

thereby eiiect a definite rate of differentiation.

MAURITZ G. INDAHL. 

